6/13 final project(color organ)

       Today, we presented our final project in the class. Our project is the color organ which is a device will convert the input signal. Our design of the project is that we have 5 different sides, 4 sides have LED lights set up and one side has speakers which will output the music we want to play. Our design is pretty successful because the product we build is working and looks cool. The following photos show how we actual build our product:

This is the circuit we used.

This is the simple color organ we build.

This is when we are building our final product.

6/8 Passive RL Filter

           The purpose of this lab is the observe how the passive RL filter circuit works and find the relationship between Vo and Vin. We will measure the value of   VR and VL then plot the graph.

1. Pre-Lab: we need to determine the frequency responses of both VL and VR:

This is the result of our colculation.


Then we start doing the experiment.
Before the cut off frequency:

After the cutoff frequency:

Before cutoff voltage:



After cutoff voltage:




After finding all the values of VR and VL, we need to plot the graph of these two:

Summary

             In today's class, we further study the importance of the filter. We also learned 3 different types of filter:low passive filiter, high filter and Band pass filter 

We also did some examples of the filter:

6/6 No Lab Today

Summary

     In today's class, we learned the definition of transfer function. The equation for transfer function is :

This is the output VS. input. There are many different transfer functions like current transfer function, voltage transfer function and so on. The most important concept we learned today is how to plot the graph of transfer function. First, we need to change the function to the standard form then graph each component of the function. At last, combine all the graphs together to get an overall graph. 

These are some examples we did during the lecture time:

5/30 Signals with Multiple Frequency Components

     The purpose of this lab is to verify the equation of transfer function: at very low frequencies, the capacitor has infinite impedance, the circuit becomes a simple voltage divider. At very high frequencies, the capacitor;s impedance is zero, the capacitor behaves like a short circuit.

Pre-Lab calculation:

The following photos are the result of our experiment :

This is the graph of output and input voltage. Yellow line is the output and the blue one is the input.

Using the sweep function we will have another photo: 

Summary

        In today's class, we learned the concept of transfer function: 

here is the graph of the transfer function: 

Also, the following picture is the related equation for transfer function: 

This is the example we did during the lecture time: 

5/25 Apparent Power and Power Factor

        The purpose of this lab is to find the apparent power and the power factor through the experiment method. Then compare the theoretical value and the experimental value to see the percent error.

1. Pre-Lab calculation:

And this is the final calculation result:

This is the actual set up of our lab:

Following are the result of our lab:

Load resistance = 10 ohms

The RMS value of load voltage is 627mV.

The RMS value of load current is 18.7mA.

The phase difference is 64.44 degree.

Load Resistance = 47 ohms

The RMS value of load voltage is 625.1mV.

The RMS value of load current is 10.68mA.

The phase difference is 36.83 degree.

Load Resistance = 100 ohms

The RMS value of load voltage is 660.1mV.

The RMS value of load current is 6.22mA.

The phase difference is 12.6 degree.

Summary

          In today's class, we further learned how to calculate the apparent power and power factor. Also, we discussed when will the power of load resistance reach the maximum. The following picture are some formulas that can help us better understand power:

 

5/23 Op Amp Relaxation Oscillator

           The purpose of this Lab is to observe how the Rekaxation Oscillator circuit actually works through the experimental method. Then, compare the theoretical value and the experimental value. Analyzes the differences.
Pre- Lab Calculation:

This is the actual set up of our experiment:

1. The following photo is the result of our lab:

Compare to the result from the everycircuit:

Summary 

           In today's class, we learned the concept of oscillator. One important feature of oscillator is that it is able to change the AV current to the DC current which is really important in our daily life.

5/18 No Lab Today

Summary 

    In today's class, we are learning the convert between the frequency and phasor domain. And practice the calculations of these formula. Then, did some example questions.

5/16 Impedance

    The purpose of this lab to find the actual impedance of the circuit through the experiment method. And also observe the effect of the impedance to the circuit.

1. Pre Lab calculation:

2.This is the actual set up of our lab

The following photos are the result of our experiment

100 ohms and 5K Hz and no phase shift

                                                  I = 13.27mA   V = 1.367V

100 ohms and 5K Hz and 32.5 degree phase shift

I = 34mA     V = 1.06V

100 ohms and 5K Hz and 82.8 degree phase shift

I = 6.2mA    V = 2.05V

Summary 

     In today's class, we are introduced the concept of impedance. We can calculate the impedance of capacity and inductor. Then, trade them as resistance.